Tail light mystery! Help

[Crazypierre]

Hi,
So, the rear n/s light bulb doesn't light up. But the bulb is fine and not blown.  I also tried a new bulb and that doesn't work either.
I put a voltmeter onto the bulb holder contacts and there is power getting to the bulb holder.

So, I'm flummoxed....what could be wrong?

It's a 79 131 1300CL by the way. The one with the big rectangular lights.

Cheers
Pete

[mirafioriman]

If there is a live and an earth at the bulb holder it can only be a bad bulb or a bad connection between the bulb and the bulb holder I would have thought.

[Crazypierre]

Hi Dave,
There is definitely power at he bulb holder. I put one voltmeter prong on the little sprung tongue in the middle of the bulb holder and the other prong on the side of the holder and it's reading 11.5 volts or so.

i even shaped a little hook from some wire and pulled the sprung tongue out a little to ensure good contact with the bulb but still nothing.

Pete

[mirafioriman]

I'm going for a bad earth connection between the bulb and holder.

[Crazypierre]

Hi Dave,
Can you explain what you mean please?  Do you mean one of the two wires that go to the bulb holder? Or do you mean a third (earth) wire like you get on domestic fittings- the ones that are green in domestic fittings?

Thanks
Pete

[mirafioriman]

The spring contact at the bottom of the holder supplies the +ve connection the -ve connection comes from the outside of the bulb holder. This seems to be the weak link with these I've had problems in the past with bad connections too.

[Crazypierre]

Hi,
OK, it's working again. I started removing the whole unit from the inside of the boot and the movement seems to have fixed the bad connection.

Thanks all.
Pete